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- Describe an experiment to investigate the effects of unilateral source of light on growth of seedlings.(Solved)
Describe an experiment to investigate the effects of unilateral source of light on growth of seedlings.
Date posted: May 24, 2019. Answers (1)
- In an experiment, 900 viable seeds of a certain plant species were divided into groups of 100 seeds each. Each group of
seeds was placed at...(Solved)
In an experiment, 900 viable seeds of a certain plant species were divided into groups of 100 seeds each. Each group of
seeds was placed at different temperatures but same conditions of air and moisture. The percent germination was
determined after 10 days. The table below shows percent germination at the various temperatures.
a) Using a suitable scale, draw a graph of percent germination against temperature.
b) Account for percent germination at :
i) 50°
ii) 30°C
iii) 40°C
c) Explain the role played by each of the following factors in the germination of seeds.
i) Water.
ii) Air.
Date posted: May 24, 2019. Answers (1)
- State TWO features of the endodermis.(Solved)
State TWO features of the endodermis.
Date posted: May 24, 2019. Answers (1)
- The diagram below represents phloem tissue from the stem of a plant.
i) Name the structure labelled A.
ii) State TWO substances transported in the phloem....(Solved)
The diagram below represents phloem tissue from the stem of a plant.
i) Name the structure labelled A.
ii) State TWO substances transported in the phloem.
iii) Give the function of cell B.
Date posted: May 24, 2019. Answers (1)
- Three sterilized petri dishes I, II and III were half filled with sterilized nutrient agar jelly and then treated as shown below.
The petri dishes were...(Solved)
Three sterilized petri dishes I, II and III were half filled with sterilized nutrient agar jelly and then treated as shown below.
The petri dishes were then kept in an oven at 36°C. After 2 days the three petri dishes were flooded with iodine solution.
a) Yellow spots were noted in set up I and II while set up III turned blue black.
i) What was the importance of sterilization in the experiment?
ii) Mention TWO ways by which sterilization could have been achieved.
b) Explain the results obtained in each of the three petri dishes after 2 days.
Date posted: May 24, 2019. Answers (1)
- 50cm³ of 10% glucose solution was boiled and allowed to cool. The solution was then poured into a vacuum flask and about
5cm³ of groundnut oil...(Solved)
50cm³ of 10% glucose solution was boiled and allowed to cool. The solution was then poured into a vacuum flask and about
5cm³ of groundnut oil added to it. 10% yeast solution was introduced into the glucose solution using a pipette. A
thermometer was placed in the flask and supported with a cotton wool plug. A second flask was set up as above, but
containing cooled boiled water instead of 10% glucose solution. The temperature of each flask was recorded at the
beginning and thereafter at hourly intervals for several hours.
a) Why was a vacuum flask used in this experiment?
b) What was the purpose of the second flask?
c) Write a word equation to summarize the reaction that took place in the first flask.
d) Why was groundnut oil added to the flask?
e) Why was it necessary to boil the glucose and the water before they were poured into the flask?
Date posted: May 24, 2019. Answers (1)
- Distinguish between obligate and facultative anaerobes.(Solved)
Distinguish between obligate and facultative anaerobes.
Date posted: May 24, 2019. Answers (1)
- Haemophilia is a bleeders disease. The disease is caused by a recessive gene which is carried in the X chromosome. XH
stands for normal gene whereas...(Solved)
Haemophilia is a bleeders disease. The disease is caused by a recessive gene which is carried in the X chromosome. XH
stands for normal gene whereas Xh stands for haemophilia gene. The figure below shows a family tree.
a) What is the genotype of
i) Mother
ii) Son marked 2
iii) Daughter marked 1
b) If the haemophilia son marries a girl who has no history of haemophilia in her family, what will be the genotype of the
offspring ? (Show your working)
Date posted: May 24, 2019. Answers (1)
- The diagram below represents recycling of nutrients in a certain ecosystem.
a) Name the trophic level represented by M.
b) Name the processes represented by. I,II,III...(Solved)
The diagram below represents recycling of nutrients in a certain ecosystem.
a) Name the trophic level represented by M.
b) Name the processes represented by. I,II,III
c) Name the organisms involved in process II.
d) What would happen within the ecosystem if all secondary consumers were eliminated?
Date posted: May 24, 2019. Answers (1)
- State ONE cause of variations in organisms that take place during gametogenesis.(Solved)
State ONE cause of variations in organisms that take place during gametogenesis.
Date posted: May 24, 2019. Answers (1)
- What is the meaning of the following terms?
i) Fermentation.
ii) Oxygen debt.(Solved)
What is the meaning of the following terms?
i) Fermentation.
ii) Oxygen debt.
Date posted: May 24, 2019. Answers (1)
- Name the cell organelles that are responsible for the formation of the following organelles.
i) Lysosomes
ii) Ribosomes(Solved)
Name the cell organelles that are responsible for the formation of the following organelles.
i) Lysosomes
ii) Ribosomes
Date posted: May 24, 2019. Answers (1)
- State one disadvantage of using quadrat method in population estimation.(Solved)
State one disadvantage of using quadrat method in population estimation.
Date posted: May 24, 2019. Answers (1)
- The following diagram shows a feeding relationship in an ecosystem.
From the diagram, write down a food chain with crocodile as the tertiary consumer.
(Solved)
The following diagram shows a feeding relationship in an ecosystem.
From the diagram, write down a food chain with crocodile as the tertiary consumer.
Date posted: May 24, 2019. Answers (1)
- The diagram below represents the internal structure of a bean seed.
a) Name the parts the seed embryo represented by letter X and Y.
b) What...(Solved)
The diagram below represents the internal structure of a bean seed.
a) Name the parts the seed embryo represented by letter X and Y.
b) What type of germination would result if the hypocotyl elongates faster.
c) What is the significance of the part labelled Y emerging first during germination.
Date posted: May 24, 2019. Answers (1)
- Plants of a particular species growing in certain habitat flower at the same time. What is the importance of this adaptation.(Solved)
Plants of a particular species growing in certain habitat flower at the same time. What is the importance of this adaptation.
Date posted: May 24, 2019. Answers (1)
- Describe how osmotic pressure develops.(Solved)
Describe how osmotic pressure develops.
Date posted: May 24, 2019. Answers (1)
- What is carapace?(Solved)
What is carapace?
Date posted: May 24, 2019. Answers (1)
- An investigation was carried to show the effect of antidiuretic hormone (ADH) on urine production in a mammal. The rate of urine production was measured...(Solved)
An investigation was carried to show the effect of antidiuretic hormone (ADH) on urine production in a mammal. The rate of urine production was measured over a period of 30 minutes. Five minutes after measurements began; ADH was injected into a vein of the mammal. The results are shown in table below.
a) Plot a graph of rate of urine production against time.
b) Name the gland that releases ADH.
c) Describe the effect of injection of ADH on the rate of urine production in the mammal in this investigation.
d) Describe the mechanism by which ADH produces the effect seen in this investigation.
e) In a similar investigation, an injection of sodium chloride (salt) solution was given after five minutes instead of ADH. This injection was observed to affect urine production in a similar way to ADH. Suggest how the sodium chloride brought about this effect.
Date posted: May 24, 2019. Answers (1)
- State any two differences between an ovum and a sperm.(Solved)
State any two differences between an ovum and a sperm.
Date posted: May 24, 2019. Answers (1)